A year and a half ago, Jamba (Nasdaq: JMBA) was in dire straits. It had little cash, lots of debt , and big operating losses. Investors were starting to worry about bankruptcy, and the company knew it had to get rid of the debt somehow. But it couldn't really raise money by issuing new shares while the stock was trading for dimes.

So Jamba made its deal with the devil, and issued $35 million worth of convertible preferred shares. Like any Faustian bargain, I suppose, there is some good and bad involved -- and we're beginning to see both play out.

Preferred shares have characteristics of both debt and stock. On the one hand, the shares earned an 8% annual cumulative dividend, meaning that if the company couldn't pay the dividend at any point, it would still accrue, and Jamba would be on the hook to pay it later – similar to a bond's coupon. On the other hand, the shares -- individually priced at $115 -- could be converted into 100 shares of common stock priced at $1.15 apiece.

This arrangement was not too different from the one Berkshire Hathaway's (NYSE: BRK-A)(NYSE: BRK-B) Warren Buffett struck with Goldman Sachs (NYSE: GS) in the midst of the financial panic of 2008. That move may have saved Goldman from insolvency, but it now reportedly costs the company $1.3 million per day in dividends. (Clearly, it's good to be the Oracle.)

The Jamba deal is of course much smaller in scope, but still costly. In the last quarter, the company reported net income of $1.6 million, but , but the preferred dividend cost it nearly $600,000. Without the dividend, earnings available to common shareholders would have been substantially higher.

The good news for cash flow? Unlike Warren Buffett, the preferred shareholders don't seem interested in holding their investment for the long term. Since the issue, more than 100,000 preferred shares have been converted to common stock and sold year to date -- representing more than one-third of the initial stake. Each conversion means money saved on dividends that no longer have to be paid.

Unfortunately, each conversion and sale also means a stock dilution. If all of the preferred shares (as of the last report) get converted, the number of common shares will rise to some 83 million -- a 40% dilution.

The preferred share issue was necessary at the time, but as the company recovers, it will prove to be a burden. Fortunately, that burden seems to lightening -- even if that development comes with its own problems.